A random access is an important function of a modern cellular mobile communication system, and in numerous scenarios, a subsequent operation can proceed only after a random access function is performed.
A non-contention random access process in an existing Long Term Evolution (LTE) system is as follows.
As illustrated in FIG. 1, an evolved NodeB (eNodeB) selects a dedicated preamble for a User Equipment (UE), and the UE provided with the dedicated preamble transmits the dedicated preamble over a Physical Random Access Channel (PRACH) selected by the UE.
The eNodeB can control the dedicated preamble to be used only by the UE, therefore, a collision is avoided, the probability of a successful random access of the UE is improved and a delay of the access is reduced effectively.
At present, no specific PRACH resource is designated when the dedicated preamble is allocated, and the UE may select randomly the PRACH resource, which means that a collision can be avoided absolutely only if the dedicated preamble over all of PRACHs is allocated to the UE during a valid period of the dedicated preamble. However, the UE may finally select only one of the PRACHs for transmission of the dedicated preamble, therefore, the dedicated preamble over the other PRACH resources is indeed wasted.
In summary, resources are utilized inefficiently because the UE selects the PRACH resource for transmission of the dedicated preamble allocated by the eNodeB during a random access in the prior art.